Reland of Add automated testing to check for page size with scaling

components/printing/test/mock_printer.cc

Index: components/printing/test/mock_printer.cc
diff --git a/components/printing/test/mock_printer.cc b/components/printing/test/mock_printer.cc
index 4197dc603b584709e98e3d2d92c279e943983473..1a38b7a08aa8033e1ae3bd0a71d87c07e8cb3d4e 100644
--- a/components/printing/test/mock_printer.cc
+++ b/components/printing/test/mock_printer.cc
@@ -38,6 +38,13 @@
     params->margin_left = static_cast<int>(0.30 * dpi);
     params->margin_top = static_cast<int>(0.30 * dpi);
   }
+}
+
+void UpdatePageSizeAndScaling(const gfx::Size& page_size,
+                              int scale_factor,
+                              PrintMsg_Print_Params* params) {
+  params->page_size = page_size;
+  params->scale_factor = static_cast<double>(scale_factor) / 100.0;
 }
 
 }  // namespace
@@ -161,7 +168,9 @@
 void MockPrinter::UpdateSettings(int cookie,
                                  PrintMsg_PrintPages_Params* params,
                                  const std::vector<int>& pages,
-                                 int margins_type) {
+                                 int margins_type,
+                                 const gfx::Size& page_size,
+                                 int scale_factor) {
   if (document_cookie_ == -1) {
     document_cookie_ = CreateDocumentCookie();
   }
@@ -169,6 +178,8 @@
   params->pages = pages;
   SetPrintParams(&(params->params));
   UpdateMargins(margins_type, dpi_, &(params->params));
+  if (!page_size.IsEmpty())
+    UpdatePageSizeAndScaling(page_size, scale_factor, &params->params);
   printer_status_ = PRINTER_PRINTING;
 }